Sunday, May 30, 2010
Tip of The Month: Block Out That Dirt !
A fellow DomesRO reader asked if there is a "do-it-yourself" method or mod on how to prevent debris, dirt and/or hair from accumulating into the gears of a 500 series Roomba cleaning head module (CHM) and I said YES! The mod comes from the mind of fellow domestic robot fanatic Ed Vickery (a.k.a. "vic7767"). He is a huge contributor at RobotReviews and I have known him for many years from helping out human beings with their sick and tired domestic robots. Keep in mind that these steps created by Ed are for the technically inclined (which is most of us here); for those who do not have the time and/or expertise Ed (a.k.a. "vic7767") can do this mod for a modest service fee. So are you ready to hack your 500 series iRobot Roomba?! Yes? Then just follow these 16 "easy" steps and enjoy!
The Sealed ball bearings used are:
1) 6 x 10 x 3 mm bearing for the brush motor from VXB.com
2) 10 x 15 x 4 mm bearing for the small rubber brush
3) 15 x 21 x 4 mm bearing for the large brush.
The 15 mm inside diameter ball bearing does not allow much clearance between the square portion of the brush gear and the wall of the ball bearing. If one is concerned you may substitute a larger ID sealed bearing like the 17 x 26 x 5 mm instead but you will have to cut away some of the plastic from the wire brush retainer.
This mod does not cover the actual removal of the CHM from the Roomba. The owners manual and online video at the iRobot site should help the owner with the actual removal of the CHM.
STEP 6: Once the motor is removed it can be turned around and kept in place out of the way using some clear tape.
STEP 8: With plate removed you will be able to access the six gears and the surrounding area to wipe out the lubricant applied during assembly.
STEP 9: Once the six gears are removed they can be cleaned of the lubricant by using liquid soap and a toothbrush.
STEP 10: When filing down the diameter of the brush motor gear a small screw and nut can be used to hold the gear and insert the screw into the end of the drill.
STEP 11: The two larger gears can be inserted into the drill using the metal shaft that is already installed in each. As the diameter is filed down on each gear a test fitting of the ball bearing should be done from time to time so that the bearing has a tight fit.
STEP 12: There are three basic tools that can be used to enlarge the diameter of the holes for the gear assembly. The first tool is a "step drill", the second is a shank mounted grinding stone, and the third is a fine round file.
STEP 13: As each hole is enlarged just enough for a tight fit of the gear with the bearing installed on it, a test fit of the gear next to it can also be done. This helps verify that the gear alignment will be true when all three bearing gears are installed. After all gears are in place the gear cover plate can be trial fitted to make sure the gears are in alignment.
NOTE: The bearing will bind if they are fitted too tight into the hole.
STEP 14: When installing the brush motor check that the motor is in proper alignment with the Green deck and that the deck height adjustment wire is stretched out so the end of it can be reinserted into the slit in the blue cage.
STEP 15: After white lithium grease is applied to the gear teeth surfaces and the metal shafts, install the gear assembly access cover with the six screws. This part will be difficult for most but you might be able to at least test and verify the brush motor and gears will operate without much resistance. Try using a 9 volt battery connected to the red and black leads of the paddle board and verify that the gear assembly will spin. If you can test the amount of current being consumed by the brush motor make sure it is below .5 amps at 16 volts.
STEP 16: Finally install the Green brush assembly back into the blue CHM cage. Make sure the paddle board is in place and the screws tightened so they are flat with the blue plastic case. Make sure the brush deck height adjustment wire is in place and the Red DOT in place or a piece of tape over the plastic slot.
Wow! You reached the end! Hope that this great tip from Ed (a.k.a. "vic7767") has helped you block out the dirt from your Roomba 500 series gear box so it can provide you many years of efficient service.